J Intl Cooper Agric Dev 2014; 13: 69–74

Journal ofInternational Cooperation for
Agricultural Development

Case Report

Trial on Hybrid Method of RiceCultivation (HYMERIC) in Mwea, Kenya
Hikaru Niki1), Raphael Wanjogu2) and Vincent Kipngetich2)
1) Japan International Cooperation Agency2) Mwea Irrigation Agricultural Development Centre, National Irrigation Board, Kenya
論文受付 2013 年 3 月 7 日
Abstract. A new rice cultivation method called Hybrid Method of Rice Cultivation (HYMERIC) was introduced in TimorLeste in 2009 for the first time. This new method was tried at Mwea Irrigation Scheme in Kenya in 2010 main season (shortrain). In a word, this HYMERIC is a modification of “Rice Cultivation by Using Broadcastable Seedlings” which wasintroduced by Dr. Seizo Matsushima in 1975 (Matsushima 1980) using nursling seedlings (Hoshikawa 1994). The featuresof this method are; utilizing local materials such as husk charcoal, minimum cost of seedbed and transplanting, high numberof productive tillers, and eventually low-cost high yielding could be anticipated. As a result of the trial and the measurementof whole harvested rice, 6,000 kg ha–1, 6,160 kg ha–1 and 7,333 kg ha–1 were obtained by normal puddling, normal puddlingin economic scale and minimum tillage, respectively. Besides, four samples were harvested from each treatment by threediagonal method, and those results were analyzed statistically. Harvested area for each sample was 4 m2 (2 m × 2 m). The
analysis indicated that there was a high coefficient correlation between number of hills per m2 and yields. All in all, regression
curve was obtained. HYMERIC method could be used by small scale poor farmers.
Key words: CARD, Cultivation Method, HYMERIC, Kenya, Rice
要旨

東ティモール国で開発された新しい稲栽培法をケニア国ムウェア灌漑計画地区で試行した。星川により概念確立された乳苗を、松島により開発された投げ植え移植法により田植えする栽培法である。形態的には直播と移植の折衷案に近く、従って Hybrid Method of Rice Cultivation (HYMERIC) と命名された。現地調達可能な籾殻燻炭等の資材を使用し、苗作り ・ 田植え労力を大幅に削減でき、最大の有効分げつ数確保が容易であるため低コスト ・ 高収量が期待できる点が同法の特徴である。2010 年小雨期期、陸稲ネリカ品種を使用し HYMERIC が試行された。結果は通常代掻き法により 6,000kg ha–1、経済規模における同法により 6,160 kg ha–1、不耕起栽培により 7,333 kg ha–1 が得られた。この全刈り収量の他、三斜線法により各プロットから 4 サンプルが収穫され、統計分析の結果、平米当たりの株数と収量の間には高い正の相関関係が立証され、回帰曲線が得られた。

1. Introduction
Rice cultivation was introduced in Kenya in 1907 fromAsia. It is currently the third most important cereal crop
after maize and wheat. It is grown mainly by small-scale
farmers as a commercial and food crop. About 95% of therice grown in Kenya is from irrigation schemes established

Corresponding author: Hikaru Niki, E-mail: Niki.Hikaru@jica.go.jp

by Government while the remaining 5% is produced underrain-fed conditions. National rice production over the lastten years has been in the range of 60,000 to 100,000 metrictones per year against a consumption of 400,000 metrictones. The deficit is met through imports.
The Ministry of Agriculture of Kenyan Government
recently launched National Rice Development Strategy(NRDS) with the coordination of Coalition for African
Rice Development (CARD). Setting the target at 178,580
metric tons of paddy production until 2018, NRDS covers
J Intl Cooper Agric Dev 2014 69

most of the fields related to the rice sub sector in order topromote rice. However, constraints to increase rice are socomplicated that rice farmers hesitate to increase their capital to rice production. One of the reasons for impedancein rice expansion is low competitiveness of local produced
rice with imported rice which is cheap and high quality.
This current farmer’s dilemma motivated the Ministryof Agriculture to pursue low cost and high yielding ricecultivation method. Hybrid Method of Rice Cultivation(so-called HYMERIC) is one of the promising ways tosolve the problem. The method was introduced and tried
at Mwea Irrigation Agricultural Development Centre(MIAD) in Kenya at short rain season in 2010. This papertries to give the idea of HYMERIC and analyze the resultsof the trial.

Photo 1. Rice husk charcoal bedding.

2. Outline of the method
In a word, this HYMERIC is a modification of “Rice
Cultivation by Using Broadcastable Seedlings” which wasintroduced by Dr. Seizo Matsushima in 1975 (Matsushima1980). There are two major modifications from original
method, i.e. (1) seedling-box is not used, and (2) using
nursling seedlings (Hoshikawa 1994). Each cultivation
practice is explained as follows;
2.1 Seed treatment

Photo 2. Rice seeds sown on the rice husk charcoal bedding.

There is no special difference as other methods as thismethod also uses sprouting seeds which are uniform andvigorous. Optimum germination degree is about one millimeter white bud coming from lemma, which might takeone day for soaking seed and two days for germination
treatment (incubation).

one hectare by two persons including uprooting, however, one day may be enough without using the implement(guide).

2.2 Seedbed preparation

2.4 Land preparation

Carbonized husk (Husk charcoal) is used for bedding on
top of ordinary seedbed and no other material is used forseedbed. Two to three centimeters thickness of charcoal
bed is appropriate (see Photo 1). Sowing should be as
dense as 2 kg of seed per m2 that will cover whole seedbed
such that no bed is seen at all (see Photo 2). Seeds are to
be covered by same rice husk charcoal with the thicknessof one centimeter.

Main field should be carefully puddled and leveled as
any other rice cultivation method, and no other special
method is necessary. However, deliberate land preparation promises uniform growth and eventually assures highyield. If land is well leveled, zero tillage method could beapplied.

2.3 Broadcast transplanting with guide

After two to three days, sprouting is coming up fromcovered bed. This sprouted seeds, or seedlings, should bebroadcasted with a guide of 25 cm or 30 cm width (seePhoto 3, 4 & 5). Four days seedlings are already too longand tangled each other, eventually broadcasting becomedifficult. Two days seedlings are most suitable for broadcasting. In case of using guide, it takes two days to finish
70 J Intl Cooper Agric Dev 2014

2.5 Seedling standAlmost all broadcasted seedlings are lying down justafter broadcasted. Nevertheless, they start standing vigorously from the next day after broadcast and most of themstand completely within three to four days. Since eachseedling has roots and sprout, it may not sink in mud,which will keep out of seed rotten. Calper (calcium peroxide: Ca2O2) is not necessary to be coated in order to giveoxygen to broadcasted seedlings. This is a salient advantage of this cultivation method.

Photo 3. Transplanting guide used for the trial.
Photo 6. Rice seedlings 3 weeks after broadcasting.

Photo 4. Nursling seedlings 3 days after sowing, sprout canbe observed and ready to broadcast.

Photo 7. Rice seedlings 4 weeks after broadcasting.

ameliorate rice field in order to supply oxygen to root zone.
2.7 Tillering ability

Photo 5. Broadcasting two days-old seedlings with transplanting guide.

Tillering can be observed two weeks after broadcasted.
It starts from the second leave of rice plant. Therefore,high proportion of productive tillers than non-productive
tillers could be expected in this cultivation method (seePhoto 6 & 7). That is to say, more panicles per hill can be
expected that assure high yield eventually.

3. Pre-conditions
2.6 Water management of the main field

3.1 Countermeasure for weeds – planting in line

It is recommendable not to irrigate the field until all
seedlings stand that is about three to four days. However,flush water may be tolerable because young seedlings areresistant to submergence for sometime. Same irrigation
method as other cultivation methods should be applied incase of normal lowland rice varieties and minimum irrigation for NERICA varieties. Intermittent irrigation may

Just broadcasting of seedlings without planting guidemay be acceptable when herbicide could be used. However, herbicide is not recommendable where negative impact
is anticipated for environment as well as human beings.
Combination of line planting and weeder is practical andrecommendable. Therefore, a guide will be useful for line
planting in such a case.
J Intl Cooper Agric Dev 2014 71

Table 1. Major farm operations conducted for each plot

Figure 1. Plot allocation for the trial.

3.2 Land preparation

If rice field is not uniform in topography, lower part will
be submerged and rice plant may be retarded to grow ordamaged fatally. Therefore, mechanized land preparationmeans, especially with rotary cultivator, is appropriate.
Land preparation by animal traction may not assure uniform topography so that plant growth is not as expected.

4. Field trial
4.1 Procedure

The trial was conducted at the onset of short rain season.
Seed of NERICA 4 was sown on 20th September 2010 at
MIAD farm as shown in Table 1. One whole plot was subdivided into three smaller plots, i.e. minimum tillage plot(A), normal puddling plot (B) and the same treatment withbigger plot (C) as illustrated in Figure 1.
Minimum tillage plot was sprayed with Round-up(the main active ingredient is the isopropylamine salt ofglyphosate) 15 days before transplanting in order to clean
72 J Intl Cooper Agric Dev 2014

the field. The other cultivation methodology including
fertilization was followed to the standard method of Mwea
Irrigation Scheme Area.
<Fertilization>* N, P, K (25 kg N, 25 kg P, 25 kg K ha–1) at basal
application* 25 kg N ha–1 at tillering stage (15 days after transplanting)* 25 kg N ha–1 at booting stage (20 days before heading)<Seed amount>* 20 kg of NERICA 4 was sown to 10 m × 1 m (2 kg m–2)
* Seed from three quarters of the seedbed (15 kg) wasused for one acre (35.7 kg ha–1)
4.2 Results

Yield data was obtained from the measurement ofwhole harvested rice. The harvest operation of whole plot
started on 20th January and finished on 25th January 2011.
Against the anticipation, Plot A (minimum tillage plot)
yielded highest compared to other treatments. Actual yieldfrom each plot are; Plot A = 7,333 kg ha–1, Plot B = 6,000
kg ha–1, Plot C = 6,160 kg ha–1.
Beside the measurement of whole harvested rice, yieldof 4 m2 (2 m × 2 m) was measured. Plants were harvested
from 4 portions per plot by three-diagonal method (objectively random method). Number of hills per m2 and grain
weight were measured and adjusted for 14 percent grainmoisture contents. All the results of sample measurements
are shown in Table 2. Unlike in the case of whole harvested rice, yield was higher in normal puddling plots thanthe minimum tillage plots. This inconsistent result may be
due to uneven fertility of the soil and rough topography of
the trial field.
According to statistical analysis of the trial results, it
is obvious that there is quite high positive correlation between number of hills per m2 and yield. The correlation
coefficient (r) was as follow;
r =0.882514746
The result of t-test of significance was as follow;
t =12.61828181
Since the value of t with degree of freedom 10 at
P=0.001 is 4.59, it could safely be concluded that there isa high positive correlation between number of hills per m2
and yield. Meanwhile, regression coefficient was calculated and the result is as follow;b (Regression coefficient) = 20.45627066
Since the average yield is 7,538 kg ha–1, a = 7,538, andthe average number of hills per m2 is 48.5, x̄ = 48.5. All inall, regression curve is expressed as follow (see Figure 2);y (regression curve) = a + b (x – x̄ )		
= 7,538 + 20.5 × (x – 48.5)

Table 2. Number of hills per m2 and yield of rice grown byHybrid Method of Rice Cultivation (HYMERIC) under minimum tillage and normal puddling conditions
SamplenumberNumber ofhills per m2

Yield(kg ha–1)

Minimum tillage plot (A)

1
2
3
4

36.8
34.3
43.3
36.0

6,893
5,553
8,199
5,419

Normal puddling plot (B)

1
2
3
4

96.8
49.0
56.0
56.0

11,090
7,035
8,443
9,450

Normal puddling plot (C)

1
2
3
4

42.3
34.0
44.8
52.5

7,064
6,615
7,596
7,103

48.5

7,538

PlotAverage1)

Size of harvested area was 4 m (2 m × 2 m).
24.3 Future issues

Although positive correlation between number of hills
per m2 and yield is confirmed, ideal number of tillers perm2, or most suitable number of tillers per m2 in orderto obtain highest yield is remain unclear yet from thistrial. The plot with highest yield with 11,090 kg ha–1 wasachieved by 96.8 hills per m2. There is no doubt that theregression curve will be bent down by increasing numberof hills per m2 from certain point. It remains as future issue and another trial should be carried out to clarify mostideal number of hills per m2, or seed amount per ha, inorder to obtain highest yield of NERICA 4 at short rainseason. Although the ideal number of hills per m2 maydiffer according to the season, short rain or long rain, orby soil fertility or fertilization method, relatively higher
numbers, i.e. 80–90 per m2, may be desirable. If seedlings
stand rate after broadcast is assumed to be 70%, 115–130
grains number (seed) per m2 or 33 kg–38 kg seed amountper ha is required (1,000 grains weight of NERICA 4 is 29grams). Cost analysis remains unclear and further study

Figure 2. Relationship between yield and number of hills
per m2. ** significant at P<0.01

may be essential in this field. Simple cost comparison withordinary transplanting method may be beneficial.

5. Conclusion
Hybrid Method for Rice Cultivation (HYMERIC) with
NERICA is easy, low-cost and high yielding. Considering slightly higher yield than the conventional cultivation
method in Mwea irrigation scheme that is 5.0–6.0 t ha–1
(Mati 2011), HYMERIC could be an alternative cultivation
method in Kenya. The trial at Mwea in 2010 verified thisconstant performance. This method may suite for second
crop in Irrigation Scheme Areas where irrigation water isJ Intl Cooper Agric Dev 2014 73

not sufficient. Therefore, this method should be promoted
to the farmers in Mwea and other irrigation scheme areas
where there is shortage of irrigation water in second crop.
However, experiment on sowing density and cost analysis
may be required in order to stabilize HYMERIC method.

References
1. Hoshikawa, K. (1994) Rice Cultivation with Nursling
Seedlings – Illustration for Agriculture Class-, Ieno-74 J Intl Cooper Agric Dev 2014

hikari kyoukai.
2. Matsushima, S. (1980) Rice Cultivation for the Million –Diagnosis of Rice Cultivation and Techniquesof Yield Increase-, Japan Scientific Societies Press,Tokyo.
3. Mati, B.M. (2011) System of Rice Intensification(SRI) – Practical Notes for SRI Farmers, National
Irrigation Board.